Accumulator with internal heat exchanger

ABSTRACT

An accumulator with an internal heat exchanger for use in an air conditioning or refrigeration system having a compressor, a condenser, an expansion device, and an evaporator is disclosed. In operation, the accumulator is placed in the system so high pressure, high temperature refrigerant flowing from the condenser and low pressure, low temperature refrigerant flowing from the evaporator simultaneously enter and flow through the heat exchanger disposed in the accumulator whereby the low pressure, low temperature refrigerant absorbs heat and thereby cools the high pressure, high temperature refrigerant. In one embodiment, the heat exchanger comprises a tube having at least one high temperature channel and one low temperature channel extending through the interior of the tube. In a second embodiment, the heat exchanger comprises a single spirally wound coaxial tube having an outer tube and an inner tube positioned within the outer tube. In a third embodiment, the heat exchanger comprises a plurality of coaxial tubes, each coaxial tube having an outer tube and an inner tube positioned in the outer tube wherein the inner tubes are fluidly connected.

BACKGROUND OF THE INVENTION

[0001] This invention relates to an accumulator with an integral heatexchanger for use in an air conditioning or refrigeration system. Inparticular, the heat exchanger is positioned inside the accumulator suchthat liquid refrigerant from the high pressure, high temperature side ofthe system and gaseous refrigerant from the low pressure, lowtemperature side of system simultaneously flow through the heatexchanger in a heat exchange relationship. The accumulator of thepresent invention may be used with a variety of refrigerants includingR134a and carbon dioxide, despite the higher operating pressuresinherent in a system using carbon dioxide as the refrigerant.

[0002] A basic refrigeration or air conditioning system has acompressor, a condenser, an expansion device, and an evaporator. Thesecomponents are generally serially connected via conduit or piping andare well known in the art. During operation of the system, thecompressor acts on relatively cool gaseous refrigerant to raise thetemperature and pressure of the refrigerant. From the compressor, thehigh temperature, high pressure gaseous refrigerant flows into thecondenser where it is cooled and exits the condenser as a high pressureliquid refrigerant. The high pressure liquid refrigerant then flows toan expansion device, which controls the amount of refrigerant enteringinto the evaporator. The expansion device lowers the pressure of theliquid refrigerant before allowing the refrigerant to flow into theevaporator. In the evaporator, the low pressure, low temperaturerefrigerant absorbs heat from the surrounding area and exits theevaporator as a saturated vapor having essentially the same pressure aswhen it entered the evaporator. The suction of the compressor then drawsthe gaseous refrigerant back to the compressor where the cycle beginsagain.

[0003] In a typical air conditioning or refrigeration system, it isnecessary to prevent liquid from passing from the evaporator into thecompressor in order to avoid damage to the compressor. When liquidrefrigerant enters a compressor, it is known as slugging. Sluggingreduces the overall efficiency of the compressor and can also damage thecompressor. It is well known in the art to mount a suction line or lowpressure side accumulator between the evaporator and compressor. Suchsuction line accumulators act to separate the liquid and gaseous phasesof the refrigerant flowing from the evaporator. The liquid portion ofthe refrigerant will settle to the bottom of the accumulator while thegaseous phase will rise to the top of the accumulator and will besuctioned out of the accumulator by the compressor.

[0004] It is also known in the art to have an accumulator with a heatexchanger arranged on both the high pressure and low pressure sides ofan air conditioning or refrigeration system. FIG. 1 is a schematic of asystem having an accumulator arranged on both the high pressure and lowpressure sides of the system. In general, high pressure, hightemperature refrigerant exits a compressor 1 and flows into a condenser3. The high temperature liquid refrigerant exits the condenser and flowsinto a heat exchanger located in an accumulator 5. The refrigerant isdischarged from the accumulator and flows into an expansion device 7 andsubsequently into an evaporator 9.

[0005] At the same time, low temperature, low pressure refrigerantflowing from the evaporator 7 enters the accumulator and the liquidphase settles to the bottom of the accumulator, and the gaseous phaserises. The low temperature gaseous refrigerant then flows through theheat exchanger where it comes in contact with the high pressure, hightemperature liquid refrigerant from the condenser in a heat exchangerelationship. The high pressure liquid from the condenser 3 is thencooled by the low pressure, low temperature gaseous refrigerant runningsimultaneously through the heat exchanger. As a result, the liquidrefrigerant flowing from the condenser 3 to the evaporator is cooled andcan thereby absorb more heat as it flows through the evaporator 7. Thegaseous refrigerant exiting the low pressure side of heat exchanger ishigher in temperature having absorbed heat from the high pressure, hightemperature liquid refrigerant. As a result, any liquid refrigerant thatmay remain in the low pressure, low temperature refrigerant will beconverted into a gas in the heat exchanger thereby reducing the risk ofhaving liquid flow into the compressor.

[0006] U.S. Pat. Nos. 5,622,055, 5,245,833, 4,488,413, and 4,217,765disclose accumulators with internal heat exchangers. In these patents,high pressure, high temperature refrigerant from the condenser is cooledas it flows through a tube that is sitting in a pool of low temperatureliquid refrigerant that has been discharged from the evaporator andcollected in the accumulator.

[0007] GB Patent No. 2316738B also discloses a low pressure sideaccumulator with an internal heat exchanger. The accumulator is dividedinto an upper and lower chamber. The heat transfer unit, two seriallyconnected tubes, is housed in the lower chamber. High temperature, highpressure refrigerant flowing from the condenser enters one end of thetubes and exits the other end and then flows to an expansion deviceevaporator. At the same time, low pressure, low temperature refrigerantfrom the evaporator is discharged into the upper chamber. Therefrigerant in the upper chamber is drawn into the lower chamber whereit flows through the lower chamber in a heat exchange relationship withhigh pressure, high temperature refrigerant flowing through the tubesbefore being discharged from the accumulator and drawn back to thecompressor.

[0008] U.S. Pat. Nos. 5,457,966 and 5,289,699 disclose a high pressureside accumulator with internal heat exchanger. In one embodiment, theheat exchanger comprises an outer shell with right and left end platesand an outer tube with a cutaway portion located within the shell. Aninner tube is housed within the outer tube and extends through the shelland both end plates. In operation, high pressure, high temperatureliquid refrigerant from the condenser enters an inlet line, which flowsinto the outer tube. The liquid refrigerant flows through the outer tubeand into the shell at the cut away portion. The liquid refrigerant isdischarged from the shell through an outlet line. At the same time, lowpressure, low temperature refrigerant from the evaporator enters thesmaller tube and flows through the inner tube in a heat exchangerelationship with the high pressure, high temperature refrigerant beforeflowing back to the compressor.

[0009] In a second embodiment, the heat exchanger housed within theshell comprises a small oval shaped tube affixed to one side of a largetube. The larger tube extends through the entire length of the shell.High pressure, high temperature liquid refrigerant from the condenserenters one end of the oval shaped tube and exits the other end and flowsinto the shell. Liquid refrigerant exits the shell through an outletline and flows to the evaporator. Simultaneously, low pressure, lowtemperature refrigerant flows from the evaporator through the large tubein a heat exchange relationship with the high pressure, high temperaturerefrigerant. The low pressure, low temperature refrigerant exiting thelarger tube flows back to the compressor. A third embodiment is similarto the second embodiment except that the smaller tube is spirallywrapped around the outside of the larger tube.

[0010] U.S. Pat. No. 3,830,077 discloses a heat exchanger for use in avehicle, which is connected between the evaporator and compressor. Theheat exchanger comprises an outer shell with low pressure, lowtemperature inlet and outlet lines and at least one heat exchange coil,with an inlet end an outlet end both extending through the shell. Inoperation, low pressure, low temperature refrigerant enters the inletline, flows through the shell, exits the outlet line and flows back tothe compressor. At the same time a high temperature vehicle fluid flowsthrough the coil in a heat exchange relationship with the lowtemperature, low pressure refrigerant. The patent does not specificallydisclose connecting the heat exchange coil to the high pressure, hightemperature side of the air conditioning system.

[0011] Finally, published EP Patent Application No. EP 0837291A2discloses the use of a sub cooling circuit to cool high pressure, hightemperature carbon dioxide refrigerant in a vehicle air conditioningsystem. The sub cooling circuit is located between the condenser andmain expansion device and comprises a subpressure reducer and a heatexchanger. In operation, the high pressure, high temperature carbondioxide refrigerant from the condenser is split into two flows, thefirst flow flows into the sub cooling circuit where it is cooled bypassing through the pressure reducer before flowing through heatexchanger. The second flow of refrigerant passes directly through theheat exchanger where it is cooled by the first flow.

[0012] The application discloses two different types of heat exchangers.The first heat exchanger comprises a double circular tube structurewhich has an inner tube surrounded by an outer tube with fins separatingthe tubes. Lower temperature carbon dioxide refrigerant flows throughthe inner tube in a heat exchange relationship with higher temperaturerefrigerant flowing through the outer tube.

[0013] The second heat exchanger comprises a spiral tube structureformed from two tubes soldered together. Each tube is an extrudedaluminum strip with an upper row of holes and a lower row of holes. Hightemperature carbon dioxide refrigerant flows through both rows of holesin one tube while lower temperature refrigerant flows through both rowsof holes in the second tube in a heat exchange relationship. EP PatentApplication No. 0837291A2 does not disclose having high temperature andlow temperature refrigerant flowing through one tube at the same time.Furthermore, EP Patent Application No. 0837291A2 does not disclosecombining the heat exchanger in the sub cooling circuit into anaccumulator. Thus, the disclosed air conditioning system is morecomplicated than necessary having an extra sub cooling circuit, whichcan be eliminated by the present invention.

[0014] While the above accumulators and heat exchangers are suitable fortheir intended purpose, it is believed that there is a demand in theindustry for an improved accumulator with an internal heat exchanger,especially one that can withstand the higher pressure requirements of anair conditioning or refrigeration system employing carbon dioxide as arefrigerant. It is further believed that there is a demand for animproved accumulator with an internal heat exchanger that is compact,easily assembled, lighter weight, and less costly to manufacture, butyet provides a high level of efficiency.

BRIEF SUMMARY OF THE INVENTION

[0015] The present invention provides an improved accumulator for use inan air conditioning or refrigeration system, and in particular, providesan accumulator with an improved compact heat exchanger. The improvedaccumulator may be used in existing air conditioning and refrigerationsystems utilizing R134a as the refrigerant as well as in newer systemsutilizing carbon dioxide as the refrigerant. The improved accumulatorcan easily withstand the higher pressures resulting from the use ofcarbon dioxide refrigerant.

[0016] The improved heat exchanger has a high heat transfer efficiencyresulting in an increase in the coefficient of performance (COP) for theair conditioning or refrigeration system. As a result, the airconditioning or refrigeration system has greater cooling capacity. Thisgreater cooling capacity allows for more rapid “pull down” or coolingwhen the air conditioning or refrigeration system is first started.

[0017] In addition, the accumulator of the present invention providesincreased protection against slugging in the compressor by ensuring thatany liquid remaining in the refrigerant being drawn back into thecompressor is vaporized in the heat exchanger. Finally, the heatexchanger of the present invention is easy to manufacture and is lighterin weight because all of the components may be made from aluminum.

[0018] According to one embodiment of the present invention, theaccumulator has a housing with a top and a bottom such that the housing,top, and bottom form a chamber. The accumulator has a high pressureoutlet port and a low pressure inlet port extending through the top andinto the chamber, and a high pressure inlet port and a low pressureoutlet port which are external to the housing. A vapor conduit tube anda heat exchanger are disposed in the chamber. The heat exchangercomprises at least one tube having a low temperature channel and a hightemperature channel, each channel extending through the interior of thetube. At one end of the tube, the high temperature channel is connectedto the high pressure inlet port and the low temperature channel isconnected to the low pressure outlet port. At the other end of the tube,the high temperature channel is connected to the high pressure outletport and the low temperature channel is connected to the vapor conduittube.

[0019] In operation, high pressure, high temperature refrigerant fromthe condenser enters the accumulator and then the heat exchanger throughthe high pressure inlet port. The high pressure, high temperaturerefrigerant flows through the high temperature channel and exits theheat exchanger and the accumulator through the high pressure outletport. Simultaneously, low pressure, low temperature refrigerant flowsthrough the low temperature inlet port into the chamber and is conveyedthrough the vapor conduit tube to the heat exchanger. The low pressure,low temperature refrigerant then flows through the low temperaturechannel in a heat exchange relationship with the high pressure, hightemperature refrigerant flowing through high temperature channel therebycooling the high pressure, high temperature refrigerant.

[0020] In a second embodiment of the present invention, the accumulatorlikewise has a housing with a top and bottom such that the housing, topand bottom form an internal chamber. High pressure, high temperatureinlet and outlet ports as well as low temperature inlet and outlet portsextend through the top of the accumulator into the chamber. A vaporconduit tube and a heat exchanger are disposed in the chamber. The heatexchanger comprises a coaxial tube having an outer tube and an innertube disposed within the outer tube. At one end of the coaxial tube, thehigh pressure, high temperature inlet port is attached to the inner tubeand the low pressure, low temperature outlet port is attached to theouter tube. At the other end of the coaxial tube the high pressure, hightemperature outlet port is attached to inner tube and the vapor conduittube is attached to the outer tube.

[0021] In operation, high pressure, high temperature refrigerant fromthe condenser enters the accumulator and then the heat exchanger throughthe high pressure inlet port. The high pressure, high temperaturerefrigerant flows through the inner tube and exits the heat exchangerand the accumulator through the high pressure outlet port.Simultaneously, low pressure, low temperature refrigerant flows throughthe low temperature inlet port into the chamber and is conveyed throughthe vapor conduit tube to the heat exchanger. The low pressure, lowtemperature refrigerant then flows through the outer tube in a heatexchange relationship with the high pressure, high temperaturerefrigerant flowing through the inner tube thereby cooling the highpressure, high temperature refrigerant.

[0022] In a third embodiment of the present invention, the accumulatorhas a housing, a top, and a bottom such that the housing, top, andbottom form a chamber. The chamber is divided into an upper chamber anda lower chamber by a separator. The accumulator further has low pressureinlet port and a vapor conduit extending through the top, the upperchamber and the separator before terminating in the lower chamber. Theinternal heat exchanger comprises a plurality of coaxial tubes, eachcoaxial tube having an outer tube and an inner tube disposed within theouter tube. The inner tubes of the coaxial tubes extend through the top,upper chamber, separator, lower chamber and bottom of the accumulator.The outer tubes extend from the top in the upper chamber through theseparator and terminate in the lower chamber. The inner tubes areinterconnected to allow refrigerant to circulate through each innertube.

[0023] In operation, the high pressure, high temperature refrigerantflows from the condenser and enters the connected inner tubes. Therefrigerant flows through the tubes before being discharged from theaccumulator. At the same time, low pressure, low temperature refrigerantfrom the evaporator enters the low pressure inlet port and flows intothe accumulator. The low pressure, low temperature refrigerant thenflows through the outer tubes in a heat exchange relationship with therefrigerant flowing through the inner tubes and is deposited in thelower chamber. The low pressure, low temperature refrigerant is thendrawn into the vapor conduit tube and is discharged from theaccumulator.

[0024] Further features and advantages of the present invention will beapparent upon reviewing the following detailed description andaccompanying drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0025]FIG. 1 is a schematic of an air conditioning system using theaccumulator-heat exchanger of the present invention;

[0026]FIG. 2 is an exploded view of a first embodiment of an accumulatorof the present invention;

[0027]FIG. 3 is a cross-sectional view of the accumulator of FIG. 2taken along line 1-1;

[0028]FIG. 4 is a top cross-sectional view of the accumulator of FIG. 3taken along line 2-2;

[0029]FIG. 5 is a cross-sectional view of one embodiment of a heatexchanger of the present invention;

[0030]FIG. 6 is an elevational view of a heat exchanger of the presentinvention;

[0031]FIG. 7 is a cross-sectional view of the heat exchanger of FIG. 6taken along line 3-3;

[0032]FIG. 8 is a plan view of a second embodiment of an accumulator ofthe present invention;

[0033]FIG. 9 is a cross-sectional view of the accumulator of FIG. 8taken along line 4-4;

[0034]FIG. 10 is a cross-sectional view of the accumulator of FIG. 8taken along line 5-5;

[0035]FIG. 11 is a partial exploded view of the second embodiment of thepresent invention;

[0036]FIG. 12 is a cross-sectional view of one end of the heat exchangerof the second embodiment of the present invention;

[0037]FIG. 13. is an enlarged cross-sectional view of a coaxial tubeused in the heat exchanger of the second embodiment of the presentinvention;

[0038]FIG. 14 is a cut-away view of a third embodiment of an accumulatorof the present invention;

[0039]FIG. 15 is a cross-sectional view of the accumulator of FIG. 14taken along line 6-6;

[0040]FIG. 16 is a cross-sectional view of a coaxial tube used in theheat exchanger of FIG. 14 taken along line 7-7.

[0041]FIG. 17 is an exploded view of the accumulator of FIG. 14.

DETAILED DESCRIPTION OF THE INVENTION

[0042] Referring to FIGS. 2 and 3, the accumulator 15 has a housing 17with sidewalls 19, a bottom wall 21, and a cover 23 comprising a top 25and sidewalls 27. The housing 17 and the bottom wall 21 are preferablyintegrally formed to form the lower portion of the accumulator. Thecover 23 is separately formed from the housing and forms the upperportion of the accumulator. While the accumulator shown in FIGS. 2 and 3is cylindrical in shape, the accumulator of the present invention mayhave any shape, including square, rectangular or ellipsoidal.

[0043] The housing 17 and the integrally formed bottom wall 21 aregenerally affixed to cover the 23 in an abutting relationship at anoverlapping juncture 29 to form a fluid tight or sealed internal chamber31. Welding, soldering, or brazing may be used to affix the housing andcover. The cover and housing may be formed from any material that willsatisfy the structural demands placed on the accumulator. Suitablematerials include, but are not limited to, aluminum, stainless steel,and copper. In a preferred embodiment, the accumulator cover and housingare aluminum.

[0044] The top of the cover has two openings 33 and 35 for receiving alow pressure inlet port 37 and a high pressure outlet port 39respectively. The openings 33 and 35 may be circular, elliptical,square, rectangular, or any other desired shape. The low pressure inletport 37 and high pressure outlet port 39 generally correspond in shapeto the openings in the top of the cover. In a preferred embodiment, theopenings 33 and 35 are circular and low pressure inlet port and highpressure outlet ports are cylindrical in shape.

[0045] In addition, the accumulator has a low pressure outlet port 41and a high pressure inlet port 43. Preferably, high pressure inlet portand low pressure outlet port are cylindrical but may have any shapedesired. The high pressure inlet and outlet ports and the low pressureinlet and out ports may be formed from aluminum, stainless steel, copperor any other suitable material. Preferably the inlet and outlet portsare formed from aluminum.

[0046] The low pressure outlet port is affixed to the outer portion ofthe sidewall 27 by brazing, soldering welding, or the like. The highpressure inlet port is supported by a support 45 mounted on the top ofthe cover. The support 45 is generally rectangular in shape with one end47 affixed to the top of the cover, and the opposite end 49 affixed tothe high pressure inlet port. The end 49 attached to the high pressureinlet port will generally conform to the shape of the port. As shown inFIG. 2, the high pressure inlet port 43 is cylindrical and thus thesupport has a circular shaped end, which conforms directly to the radiusof curvature of the cylindrical port. The support may be attached to thecover and the high pressure outlet port by soldering, brazing, welding,or any other suitable method.

[0047] Below the support, an inverted U-shaped opening 51 is formed inthe sidewall of the cover. The housing 17 has a corresponding U-shapedopening 53 in the upper portion of the sidewall 19. When the housing andthe cover are affixed the opening 51 and the opening 53 align to from agenerally rectangular opening through which a portion of a heatexchanger 55 passes and is connected to the low pressure outlet port 41and the high pressure inlet port 43. The housing 17 further has a sump57 formed in the center of the bottom wall 21. The sump 57 collects andstores oil, which is used to lubricate the components of the airconditioning or refrigeration system.

[0048] A vapor conduit 59 with a vapor inlet end 61 and a vapor outletend 63 having a cap 65 is positioned inside the housing. Preferably,vapor the conduit is an aluminum cylindrical J-shaped tube or J-tube.However, the vapor conduit may have any other desirable shape, includinglinear, and may be formed from any suitable materials such as stainlesssteel or copper. The vapor outlet end 63 extends vertically into thelower portion of the housing and is curved at its lower most point 67.The curved portion of the J-tube extends into the housing adjacent thebottom wall. The J-tube 59 extends upwardly from the lower most point tothe inlet end 61. The J-tube 59 further has one or more openings 69 inthe curved portion of the tube, which allow small amounts of oil to bedrawn out of the sump and into the J-tube where the oil is mixed withgaseous refrigerant. The refrigerant/oil mixture eventually exits theaccumulator through the low pressure outlet port 41 and flows back tothe compressor providing needed lubrication for the compressor and othercomponents of the system.

[0049] As shown in FIGS. 2 and 3, the accumulator may also have adeflector positioned in the housing. The deflector 71 assists inseparating liquid and gaseous refrigerant entering the accumulatorthrough the low pressure inlet port from the evaporator. Low pressure,low temperature refrigerant entering the accumulator comes into contactwith the deflector causing any liquid refrigerant to flow down the sidesof the accumulator thereby preventing liquid refrigerant from enteringthe inlet end 61 of the J-tube. Gaseous refrigerant rises and is allowedto enter the inlet end 61 of the J-tube, which is positioned underneaththe deflector. The deflector can be made of any suitable materialincluding aluminum, copper, stainless steel, or plastic, and may have avariety of shapes including conical, dome, disc or cup. In a preferredembodiment, the deflector is dome shaped and formed from aluminum. Thedeflector further has an opening through which the outlet end of theJ-tube passes. The J-tube may be soldered, brazed or welded to thedeflector at the point the outlet end passes through the deflector tofrom a liquid-tight seal.

[0050] Referring now to FIG. 6, the heat exchanger 55 is formedseparately from the accumulator cover and housing and is generally anextruded tube with interior 73, exterior 75, height H and width W. In apreferred embodiment, the heat exchanger is a rectangular shaped flatextruded aluminum tube. However, the tube may have any shape includingcircular or elliptical, and may be formed from any other suitablematerial such as stainless steel, copper or plastic. Preferably, theheat exchanger has a spiral configuration with an internal end 77 and anexternal end 79. As shown in FIG. 5, the heat exchanger 55 further hasat least two adjacent channels, a high temperature channel 81 and a lowtemperature channel 83 extending through the interior 73 of the tube. Asshown in FIGS. 6 and 7, the channels preferably comprise two rows ofmicrochannels 85. In a preferred embodiment, a section of lowtemperature channel 83 is removed from the internal and external ends ofthe heat exchanger tube. As a result, the high temperature channelprotrudes beyond the low temperature channel and forms a tongue 95 withheight H′ and width W on each end of the heat exchanger.

[0051] Alternatively, the heat exchanger may be an extruded tube havingthree or more channels, an upper channel, a middle channel and a lowerchannel. In such a heat exchanger, high pressure, high temperaturerefrigerant from the condenser may flow through the middle row ofmicrochannels while low pressure, low temperature refrigerant from theevaporator flows through the upper and lower rows of microchannels inthe opposite direction.

[0052]FIG. 4 is a top sectional view of the heat exchanger having tworows of microchannels as it is positioned in the accumulator. The highpressure outlet port 39 and the vapor outlet end 63 of the J-tube areattached to the interior end of the heat exchanger. The low-pressureoutlet port 41 and the high-pressure inlet port 43 are attached to theexterior end of the heat exchanger. The low-pressure inlet port 37 isnot connected to the heat exchanger.

[0053] As shown in FIG. 2, low pressure outlet port 41 has an upper end97 and a lower end 99 with a cap 101. The lower end 99 further has anopening 103 for receiving the low temperature channel of the heatexchanger tube. The opening 103 conforms generally to the height H andwidth W of the heat exchanger. The low pressure outlet port is attachedto the heat exchanger by sliding the port over the tongue 95 and formingan abutting relationship with the low temperature channel. The J-tube 59likewise has an opening in the outlet end 63 of the tube for receivingthe heat exchanger. The opening in the upper end of the J-tube isidentical to that of the low pressure outlet port, so the J-tubeattaches to the heat exchanger in the same manner as the low pressureoutlet port. Both the low pressure outlet port 41 and the J-tube 59 maybe attached to the heat exchanger by soldering, brazing, welding, or anyother suitable method.

[0054] High pressure inlet port 43 and high pressure outlet port 39likewise have upper ends 105 and lower ends 107 with caps 109. Highpressure inlet and outlet ports also have openings 110 in the lower endof the ports for receiving the heat exchanger. In general, the openings110 conform to the width W and H′ of the tongue 95, and are D-shaped,High pressure inlet and outlet ports are attached to the heat exchangerby inserting the tongues 95 into the openings 110. Both the highpressure inlet and outlet ports may be attached to the tongue bysoldering, brazing, welding or any other suitable method.

[0055] In operation, the accumulator 15 is placed into an airconditioning or refrigeration system as shown in FIG. 1. The refrigerantflow through the system is the same as discussed with respect to FIG. 1.Therefore, only the flow through the accumulator will be specificallydiscussed. Arrows have been added to FIGS. 2-4 to illustrate the flow ofrefrigerant through the accumulator and the heat exchanger. From thecondenser, the high temperature liquid refrigerant flows into theaccumulator through the high pressure inlet port 43, and then into theheat exchanger 55 where it flows in a clockwise direction through thehigh temperature channel 81 before being discharged from the accumulatorat the high pressure outlet port 39. After being discharged from theaccumulator, the refrigerant flows to an expansion device, which metersthe amount of fluid flowing into the evaporator. Simultaneously, theprimarily gaseous refrigerant exits the evaporator and flows into thelow pressure inlet port 37 of the accumulator. The refrigerant hits thedome shaped deflector 71, and any liquid refrigerant settles to thebottom of the accumulator. The gaseous refrigerant rises and enters thevapor inlet end 61 of the J-tube 59 and then flows through the J-tubeand out the vapor outlet end 63 into the low temperature channel 83 ofthe heat exchanger. The low pressure, low temperature gaseousrefrigerant flows in a counterclockwise direction through the lowtemperature channel of the heat exchanger where it absorbs heat from thehigh pressure, high temperature refrigerant passing through the hightemperature channel. The low pressure, low temperature refrigerant vaporis then drawn out of the accumulator through the low pressure outletport 41 and flows to the compressor.

[0056] A second embodiment of the accumulator of the present inventionis shown in FIGS. 8-12. Referring to FIGS. 8-11, the accumulator 115 hasa housing 117 with sidewalls 119, a bottom wall 121, and a cover 123having a top 125 and sidewalls 127. The housing 117 and the bottom wall121 are preferably integrally formed. Similar to the previousembodiment, a sump 128 is formed in the bottom wall of the housing inthe housing. The sump 128 is similar in design to the sump previouslydiscussed, and therefore, will not be discussed in further detail. Thecover is separately formed from the housing and forms the upper portionof the accumulator. While the accumulator shown in FIGS. 8-11 iscylindrical in shape, the accumulator of the present invention may haveany shape, including square, rectangular or ellipsoidal.

[0057] The cover 123 generally fits on top of the housing and integrallyformed bottom wall 121 to form a fluid tight or sealed internal chamber129. Welding, soldering, or brazing may be used to affix the housing andcover. The cover and housing may be formed from any material that willsatisfy the structural demands placed on the accumulator. Suitablematerials include, but are not limited to, aluminum, stainless steel,and copper. In a preferred embodiment, the accumulator cover and housingare aluminum.

[0058] As shown in FIGS. 10 and 11, the accumulator has a high pressureinlet port 131, a high pressure outlet port 135, a low pressure inletport 137, and a low pressure outlet port 139. Referring to FIG. 10, theaccumulator further has a vapor conduit or J-tube 141 with an inlet end143 and an outlet end 145 positioned inside the housing. The inlet andoutlet ports as well as the J-tube may have any desired shape, and maybe formed from any suitable material including but not limited toaluminum, stainless, steel, or copper. Preferably inlet and outlet portsand J-tube are cylindrical in shape and are formed from aluminum.

[0059] The inlet end of the J-tube extends vertically into the lowerportion of the housing and is curved at its lower most point 147. TheJ-tube extends upwardly from the lower most point to its outlet end 145.The J-tube 141 further has one or more openings (not shown) in thecurved portion of the conduit to allow for lubricating oil to be drawninto the system as previously discussed with respect to the firstembodiment. As shown in FIG. 10, both the inlet and outlet ends 143 and145 of the J-tube are positioned underneath a dome shaped deflector 149.The deflector is similar to deflector 71 shown in FIGS. 2 and 3, andtherefore, will not be discussed in further detail.

[0060] A heat exchanger 151 is also disposed in the housing. Referringnow to FIGS. 10-12, the heat exchanger comprises an extruded coaxialtube with an inner tube 153 having an upper end 155 and a lower end 157and an outer tube 159 having corresponding upper and lower ends 161 and163. As shown in FIG. 13, an enlarged cross-sectional view of thecoaxial tube, the outer tube has an outer wall 162 and an inner wall164, and the inner tube has outer wall 165 and inner wall 167. Fins orseparators 169 extend radially from the outer wall 165 of the inner tubeto the inner wall 164 of the outer tube. Any number of fins may be usedseparate the inner and outer tubes. However, the greater the number offins, the more difficult it is to spirally shape the coaxial tube. Whilethe coaxial tube in FIGS. 10-12 is preferably spirally shaped, thecoaxial tube may be straight or have other configurations as desired.The inner and outer tubes as well as the fins may be formed fromaluminum, copper, or stainless steel or any other suitable material.Preferably, the inner and outer tubes are aluminum.

[0061] As shown in FIG. 12, a cross-sectional view of each end of thecoaxial tube, a portion of the upper and lower ends of the outer tube159 is removed so that sections 166 of the inner tube extend beyond theupper and lower ends of the outer tube. A cap 170 is placed on each end168 of the outer tube in order to seal the tube and prevent refrigerantfrom flowing out the ends.

[0062] Referring now to FIGS. 10 and 11, the high pressure inlet port131 extends through the cover of the accumulator, passes through anopening 171 in the deflector and extends down into the housing where itis attached to the lower end of the inner tube. The high pressure outletport 135 extends through the top of the accumulator, passes through anopening 173 in the deflector and is attached to the upper end 155 of theinner tube. Preferably, the high pressure inlet and outlet ports arecylindrical and have a diameter that is either slightly larger orslightly smaller than the diameter of the inner tube such that innertube and high pressure inlet and outlet ports may be matingly engaged.Welding, soldering, brazing or any other suitable method may be used toform a permanent seal between the high pressure inlet and outlet portsand the lower and upper ends of the inner tube.

[0063] The J-tube 141 is attached at its outlet end 145 to the upper end161 of the outer tube. As shown in FIG. 12, the outer tube has anopening 175 in the side of the upper and lower ends of the tube. Theoutlet end 145 of the J-tube has a diameter slightly less than thediameter of opening 175 and is capable of mating engagement with opening175 of the outer tube. The outlet end of the J-tube and the upper end ofthe outer tube are soldered, brazed or welded together to form a liquidtight seal. The low pressure outlet port 139 extends through the top ofthe accumulator, passes through an opening 177 in the deflector andextends vertically into the lower portion of the housing. The lowpressure outlet port 139 is attached to the lower end 163 of outer tubein the same manner the J-tube is attached to the outer tube.

[0064] In operation, the accumulator 115 is positioned in an airconditioning or refrigeration system as shown in FIG. 1. Again, the flowof refrigerant through the system is the same as discussed with respectto FIG. 1. Arrows have been added to FIGS. 10 and 11 to indicate thedirection of flow of the refrigerant through the accumulator. Therefore,only the flow through the accumulator will be discussed. High pressure,high temperature liquid refrigerant from the condenser enters the highpressure inlet port 131 of the accumulator and flows through the innertube 153 of the heat exchanger in a counter-clockwise direction. Thehigh pressure, high temperature refrigerant is then discharged from theaccumulator through high pressure outlet port 135. At the same time, lowpressure, low temperature refrigerant exiting the evaporator enters theaccumulator through the low pressure inlet port 137 contacts thedeflector 149 and flows into the accumulator housing. The gaseousrefrigerant rises and enters the inlet end 143 of the J-tube and flowsinto the upper end 161 of the outer tube. The low temperature, lowpressure refrigerant flows through the outer tube in a clockwisedirection absorbing heat from the high pressure, high temperaturerefrigerant, thereby lowering the temperature of the high pressure, hightemperature refrigerant. The low pressure, low temperature refrigerantis discharged from the accumulator through the low pressure outlet port139 and drawn back to the compressor.

[0065] A third embodiment of the accumulator is shown in FIGS. 14-17.The accumulator 180 has a top 181, an upper housing 183 with sidewalls185, a separator 187, a lower housing 189 with sidewalls 191, and abottom 193. The top, upper housing, separator, lower housing, and bottomform a fluid tight or sealed internal chamber having an upper chamber197 and a lower chamber 199. The separator 187 further has an uppersurface 201, which forms the bottom of the upper chamber, and a lowersurface 203, which forms the top of the lower chamber 199. Welding,brazing, soldering or any other suitable method may be used to join thetop, the upper housing, the separator, the lower housing and the bottomto form the accumulator. The accumulator may have any shape, but ispreferably cylindrical in shape as shown in FIGS. 14, 15, and 17. Thetop, upper housing, separator, lower housing, and bottom, may be formedfrom any material that will satisfy the structural demands placed on theaccumulator. Suitable materials include, but are not limited to,aluminum, stainless steel, and copper. In a preferred embodiment, thetop, upper housing, separator, lower housing and bottom are aluminum.

[0066] As shown in FIG. 17, a low pressure inlet port 205 has an upperend 207 and a lower end 208. The upper end 207 passes through an opening209 in top of the housing and allows refrigerant flowing from theevaporator to enter the upper chamber of the accumulator housing. Thelower end 208 may be slightly curved to direct the flow of refrigerantinto the accumulator. Alternatively, the low pressure inlet port 205 maypass through an opening 211 in the sidewall 185 of the housing as shownin FIG. 14. The low pressure inlet port may have any desired shape, andmaybe formed from aluminum, stainless steel, copper or any othersuitable material. Preferably, the low pressure inlet port is acylindrical aluminum tube.

[0067] As shown in FIGS. 14, 15 and 17, a vapor conduit 213 passesthrough an opening 215 in the center of the top down into the upperchamber, and through an opening 217 in the separator, and terminates inthe lower chamber. The vapor conduit 213 has an inlet end 219, an outletend 221, and a bead 222 formed adjacent the inlet end. The bead 222abuts the lower surface of the separator and forms a fluid tight sealbetween the vapor conduit tube and the lower surface of the separator.In the embodiment shown in FIG. 14, the inlet end of the vapor conduit213 abuts the bottom 193 such that a vapor tight seal is formed. As aresult, the vapor conduit has a first opening 214 directly beneath theseparator. Low pressure, low temperature vapor deposited in the lowerchamber enters the vapor conduit through opening 214 and flows out ofthe accumulator at the outlet end 221 of the vapor conduit. A secondopening 216 is formed in the vapor conduit directly above the separator.The opening 216 allows oil, which is collected and stored in the upperchamber, to flow into the vapor conduit where it mixes with therefrigerant and provides lubrication for the compressor and other partsof the overall system.

[0068] In another embodiment shown in FIG. 15, the inlet end 219 of thevapor conduit terminates above the bottom 193. Low pressure, lowtemperature vapor in the lower chamber flows into the inlet end 219 ofthe vapor conduit. Oil stored in the upper chamber enters the vaporconduit through an opening (not shown) in the conduit directly above theseparator. The vapor conduit is preferably a cylindrical aluminum tube,but may have any desired shape, and may be formed from other suitablematerials including stainless steel and copper.

[0069] Accumulator 180 further has a heat exchanger disposed primarilyin the upper chamber. A preferred embodiment of the heat exchangercomprises four coaxial tubes generally represented at 220. Each coaxialtube is extruded and comprises an outer tube 223, 225, 227 and 229 withan open upper end 223′, 225′, 227′ and 229′, an open lower end 223″,225″, 227″, and 229″, and an inner tube 231, 233, 235, and 237 with acorresponding upper end 231′, 233′, 235′, and 237′, and a lower end231″, 233″ 235″ and 237″.

[0070]FIG. 16 is a cross-sectional view of one of the coaxial tubes. Thecross-section of each coaxial tube is identical; therefore, for purposesof simplicity, only one coaxial tube will be described in detail. Theouter tube 223 has an outer wall 239 and an inner wall 241, and theinner tube 231 has an outer wall 243 and an inner wall 245. Fins orseparators 247 extend radially from the outer wall 243 of the inner tubeto the inner wall 241 of the outer tube. Any number of fins may be usedto separate the inner and outer tubes. The inner and outer tubes as wellas the fins may be formed from aluminum, copper, or stainless steel orany other suitable material.

[0071] Referring now to FIGS. 14, 15, and 17, when the coaxial tubes 220are extruded, inner tube and outer tube are the same length.Subsequently, as shown with respect to one coaxial tube, a portion ofeach end of the outer tube 223 and the fins 247 are machined off suchthat lower end 231″ and upper end 231′ of the inner tube 231 extendbeyond the lower and upper ends 223″ and 223′ of the outer tube 223. Inaddition, at the upper end of the outer tube 223, a second portion ofthe outer tube is machined off leaving an exposed portion 249 of theinner tube 231 and a ring 251 of outer tube 223. Ring 251 functions as astopper to prevent the coaxial tube from sliding up and down in theaccumulator housing and assists in securing the coaxial tube to thelower surface 255 of the top. The coaxial tubes may be attached to thetop by brazing, welding, soldering or any other suitable method.

[0072] Each coaxial tube is positioned in the accumulator housing in thesame manner. For example, inner tube 231 extends through the top, intoupper chamber, through the separator, through the lower chamber, andexits bottom of the accumulator. In contrast, outer tube 223, extendsfrom beneath the lower surface 255 of the top through the separator andterminates in the lower chamber directly below the separator 187.

[0073] The lower end 231″ of the inner tube 231 functions as the highpressure inlet port, and the lower end 233″ of the inner tube 233functions as the high pressure outlet port for the accumulator.Preferably, inner tubes 231, 233, 235 and 237 are serially connected tofrom a continuous conduit for the flow of high pressure, hightemperature refrigerant through the heat exchanger. To that end, asshown in FIG. 14, the upper end 231′ of inner tube 231 is connected tothe upper end 237′ of inner tube 237 by a jumper 257. The jumper 257 isgenerally a U-shaped cylinder having a first end 259 and a second end261 for receiving inner tubes 231′ and 237′ respectively. The diameterof the jumper 257 is generally slightly greater than the diameter of theinner tubes of 231′ and 237′ such that the tubes are inserted into thefirst and second ends of the jumper and matingly engaged. The jumper maybe formed from aluminum, stainless steel, copper, or any other suitablematerial. The jumper 257 is preferably formed from aluminum. Welding,brazing, or soldering may be used to securely connect the jumper to theinner tubes. The lower end 237″ of inner tube 237 is connected to thelower end 235″ of inner tube 235 with a jumper 263 identical in allrespects to the jumper 257. Upper end 235′ of inner tube 235 isconnected to upper end 233′ of inner tube 233 with a jumper 265.

[0074] While the inner tubes of the heat exchanger are preferably serialconnected, they may also be connected in a parallel arrangement. Such anarrangement allows for two different high temperature fluids to becooled. For example, the upper end 231′ may be connected to the upperend 237′ by a jumper such that the lower ends 231″ and 237″ function asan inlet and outlet ports. Similarly, the upper ends 233′ and 235′ maybe connected by a jumper such that the lower ends 233″ and 235″ functionas inlet and outlet ports.

[0075] In operation, the accumulator 180 is positioned in an airconditioning or refrigeration system as shown in FIG. 1. Again,familiarity with the general flow of refrigerant through such a systemis presumed. Arrows have been added to FIGS. 14 and 15 to indicate thedirection of the flow of refrigerant through the accumulator and heatexchanger. High pressure, high temperature liquid refrigerant exits acondenser and enters lower end 231″ of inner tube 231 and flows throughall four serially connected inner tubes and is discharged through lowerend 233″ of inner tube 233 to the expansion device. At the same time,low pressure, temperature refrigerant from the evaporator enters inletport 205 and flows into the upper chamber 197 of the housing. Liquidrefrigerant flows to the bottom of the upper chamber where it is stored.Gaseous refrigerant rises and enters the upper ends 223′, 225′ 227′ and229′ of the outer tubes. The gaseous refrigerant flows down the outertubes in a heat exchange relationship with the high pressure, hightemperature refrigerant flowing through the inner tubes, and isdischarged into the lower chamber 199. The gaseous refrigerant thenflows into the inlet end 219 of the vapor conduit 213 and flows in anupward direction and exits the accumulator at the upper end 221 of thevapor conduit and flows back to the compressor.

[0076] While the invention with its several embodiments has beendescribed in detail, it should be understood that various modificationsmay be made to the present invention without departing from the scope ofthe invention. The following claims, including all equivalents definethe scope of the invention.

1. An accumulator for an air conditioning or refrigeration systemcomprising: a housing, said housing comprising an upper portion and alower portion joined together to form a chamber; a high pressure inletport for conveying a high pressure refrigerant from a condenser into theaccumulator; a high pressure outlet port for discharging the highpressure refrigerant from the accumulator to an evaporator; a lowpressure inlet port for conveying low pressure refrigerant from anevaporator into the accumulator; a low pressure outlet port fordischarging the low pressure refrigerant from the accumulator to acompressor; and a vapor conduit tube for conveying the low pressurerefrigerant in the accumulator to a heat exchanger disposed in thechamber, said heat exchanger comprising at least one tube having aninterior, a internal end, an external end, at least one low temperaturechannel, and at least one high temperature channel, each channelextending through the interior of the tube, wherein the external end ofthe high temperature channel is connected to the high pressure inletport, the external end of the low temperature channel is connected tothe low pressure outlet port, the internal end of the low temperaturechannel is connected to the vapor conduit tube, and the internal end ofthe high temperature channel is connected to the high pressure outletport.
 2. The accumulator of claim 1 wherein the housing is cylindrical.3. The accumulator of claim 1 wherein the heat exchanger is spirallywound and the internal end is located interiorly in the spiral.
 4. Theaccumulator of claim 1 further comprising a deflector positioned withinsaid housing.
 5. The accumulator of claim 4 wherein the deflector isdome shaped.
 6. The heat exchanger of claim 1 wherein said hightemperature and said low temperature channels comprise adjacent rows ofmicrochannels.
 7. The heat exchanger of claim 1 wherein the refrigerantflows through the low temperature channel in a direction opposite theflow of refrigerant through the high temperature channel.
 8. Anaccumulator for an air conditioning or refrigeration system comprising:a hollow housing having a top and a bottom joined together to form aclosed chamber; and a heat exchanger disposed in the housing, said heatexchanger comprising at least one tube defining at least one hightemperature channel therethrough, and at least one low temperaturechannel therethrough, wherein a refrigerant discharged from a condenserenters the accumulator and flows through the high temperature channelbefore being discharged to an evaporator, and a refrigerant dischargedfrom the evaporator enters the accumulator and flows through the lowtemperature channel in a heat exchange relationship with refrigerantflowing through the high temperature channel before being discharged toa compressor.
 9. The accumulator of claim 8 wherein the refrigerantflowing through the high temperature channel flows in the oppositedirection of the refrigerant flowing through the low temperaturechannel.
 10. The accumulator of claim 8 further comprising a deflectorpositioned in said housing.
 11. The heat exchanger of claim 8 whereinthe said high temperature and said low temperature channels compriseadjacent rows of microchannels.
 12. A method of operating an airconditioning or refrigeration cycle comprising: conveying condensedrefrigerant into an accumulator having an internal heat exchanger, saidheat exchanger comprising at least one tube defining at least one hightemperature channel therethrough and at least one low temperaturechannel therethrough, conveying the condensed refrigerant through thehigh temperature channel of the heat exchanger; discharging refrigerantfrom the high temperature channel and accumulator; evaporating therefrigerant; conveying the evaporated refrigerant through a vaporconduit tube positioned in the accumulator and into the low temperaturechannel to flow in a heat exchange relationship with refrigerant flowingthrough the high temperature channel; discharging the evaporatedrefrigerant from the low temperature channel and accumulator; andconveying the discharged evaporated refrigerant to a compressor.
 13. Themethod of claim 12 wherein the low temperature and high temperaturechannels comprise a plurality of microchannels.
 14. An accumulator foran air conditioning or refrigeration system comprising: a hollow housinghaving a top and a bottom; a low pressure inlet port extending through afirst opening defined in the top for conveying a refrigerant from anevaporator into the housing; a low pressure outlet port extendingthrough a second opening defined in the top for discharging refrigerantfrom a heat exchanger positioned in the housing to a compressor; a highpressure inlet port extending through a third opening defined in the topfor conveying refrigerant from a condenser to the heat exchanger; a highpressure outlet port extending through a fourth opening in the top fordischarging refrigerant from the heat exchanger to an evaporator; and avapor conduit tube having first and second ends for conveyingrefrigerant in the accumulator housing to the heat exchanger, said heatexchanger comprising an outer tube having a first outer tube end and asecond outer tube end, and an inner tube positioned within the outertube having a first inner tube end and a second inner tube end, whereinthe high pressure inlet port is attached at the first inner tube end,the high pressure outlet tube is attached at the second inner tube end,the first vapor conduit end is attached at the first outer tube end andthe low pressure outlet port is attached at the second outer tube end.15. The accumulator of claim 14 wherein the heat exchanger is spirallyshaped.
 16. The accumulator of claim 14 further comprising a deflectorpositioned within said housing.
 17. An accumulator for an airconditioning or refrigeration system comprising: a hollow housing havinga top and a bottom; a heat exchanger disposed in the housing, said heatexchanger comprising a helical coaxial tube having an outer tube and aninner tube disposed within the outer tube, wherein a refrigerant from acondenser flows into the accumulator and through the inner tube andsimultaneously a refrigerant from an evaporator flows into theaccumulator and through the outer tube in a heat exchange relationship.18. A method of operating an air conditioning or refrigeration systemcomprising: conveying condensed refrigerant through a high pressureinlet port into an accumulator having an internal heat exchanger, saidheat exchanger comprising an outer tube having a first outer tube endand a second outer tube end, and an inner tube positioned within theouter tube having a first inner tube end and a second inner tube endwherein the high pressure inlet port is attached at the first inner tubeend, a high pressure outlet tube is attached at the second inner tubeend, a vapor conduit tube is attached at the first outer tube end, and alow pressure outlet port is attached at the second outer tube end;conveying the condensed refrigerant through the inner tube of the heatexchanger; discharging the condensed refrigerant from the inner tube ofthe heat exchanger and accumulator through the high pressure outletport; evaporating the refrigerant; conveying the evaporated refrigerantinto the accumulator through the low pressure inlet port; conveying theevaporated refrigerant through the vapor conduit tube and into the outertube in a heat exchange relationship with the refrigerant flowingthrough the inner tube; discharging the evaporated refrigerant fromouter tube and accumulator through the low pressure outlet port; andconveying the evaporated refrigerant to a compressor.
 19. The method ofclaim 18 wherein the heat exchanger is helically shaped.
 20. The methodof claim 18 wherein the accumulator further comprises a deflectorpositioned within said accumulator.
 21. An accumulator for an airconditioning or refrigeration system comprising: a top, an upper shell,a plate, a lower shell, and a bottom, wherein said top, upper shell,plate, lower shell and bottom form a closed housing having an upperchamber and a lower chamber separated by the plate; a low pressure inletport extending into the upper chamber; a vapor conduit tube extendingthrough the top, into the upper chamber, through an opening in theplate, and into the lower chamber; a heat exchanger comprising aplurality of coaxial tubes at least partially within said housing, eachcoaxial tube further comprising an outer tube and an inner tube disposedwithin the outer tube, said inner tube extending through the top, intothe upper chamber, through the plate, into the lower chamber and throughthe bottom, said outer tube extending through the upper chamber, throughthe plate, and into the lower chamber.
 22. The accumulator of claim 21wherein the low pressure inlet port extends through an opening in thetop or an opening in the upper shell into the upper chamber.
 23. Theaccumulator of claim 21 wherein a high temperature refrigerant flowsthrough the inner tubes and a low temperature refrigerant flows throughthe outer tubes in a heat exchange relationship.
 24. The accumulator ofclaim 21 wherein the inner tubes are serially connected.
 25. Theaccumulator of claim 21 wherein the inner tubes are connected inparallel.
 26. The accumulator of claim 21 wherein the heat exchangercomprises a first, second, third, and fourth coaxial tube, each coaxialtube having a first, second, third, and fourth outer tube, a first,second, third, and fourth inner tube, each inner tube having an upperinner tube end and a lower inner tube end, wherein the first upper innertube end is connected to the second upper inner tube end, the secondlower inner tube end is connected to the third lower inner tube end, andthe third upper inner tube end is connected to the fourth upper innertube end.
 27. The accumulator of claim 26 wherein a high temperaturerefrigerant enters the first lower inner tube end, flows through thefour inner tubes, and exits the fourth lower inner tube end and a lowtemperature refrigerant flows through the four outer tubes in a heatexchange relationship with the high temperature refrigerant flowingthrough the inner tubes.
 28. An accumulator for an air conditioningsystem or a refrigeration system comprising: a housing, a top, and abottom, said housing, top and bottom forming a closed chamber; and aheat exchanger disposed in the chamber comprising a plurality of coaxialtubes, each coaxial tube having an outer tube enclosed in the housingand an inner tube extending through the top, chamber and bottom, whereinsaid inner tubes are fluidly connected to allow a high temperaturerefrigerant to flow therethrouh while a low temperature refrigerantsimultaneously flows through the outer tubes in a heat exchangerelationship.
 29. A method of operating an air conditioning orrefrigeration system comprising: conveying condensed refrigerant througha high pressure inlet port into an accumulator having an internal heatexchanger, said heat exchanger comprising a plurality of coaxial tubes,each coaxial tube further comprising an outer tube and an inner tubedisposed within the outer tube, wherein said inner tubes extend throughthe accumulator and are fluidly connected; conveying the condensedrefrigerant through the inner tubes; discharging the condensedrefrigerant from the inner tubes and accumulator through a high pressureoutlet port; evaporating the refrigerant; conveying the evaporatedrefrigerant into the accumulator through a low pressure inlet port;conveying the evaporated refrigerant in the accumulator through theouter tubes of the heat exchanger in a heat exchange relationship withthe condensed refrigerant flowing through the inner tubes; conveying theevaporated refrigerant into a vapor conduit tube; discharging theevaporated refrigerant from the vapor conduit tube and accumulator; andconveying the evaporated refrigerant to a compressor.
 30. A method ofcooling a high temperature liquid refrigerant in an air conditioning orrefrigeration system comprising: conveying the high temperaturerefrigerant through a heat exchanger disposed in an accumulator whilesimultaneously conveying a low temperature refrigerant through the heatexchanger, said heat exchanger comprising at least one tube defining atleast one high temperature channel therethrough, and at least one lowtemperature channel therethrough, wherein the high temperaturerefrigerant flows through the high temperature channel in a heatexchange relationship with low temperature refrigerant flowing throughthe low temperature channel.
 31. A method for cooling a high temperaturerefrigerant discharged from a condenser in an air conditioning orrefrigeration system comprising: conveying the high temperaturerefrigerant through a heat exchanger disposed in an accumulator whilesimultaneously conveying a low temperature refrigerant through the heatexchanger, said heat exchanger comprising a helically shaped coaxialtube having an outer tube and an inner tube disposed within said outertube, wherein the high temperature refrigerant flows through the outertube and the low temperature refrigerant flows through the inner tube ina heat exchange relationship.
 32. A method of cooling a high temperaturerefrigerant in an air conditioning or refrigeration system comprising:conveying the high temperature refrigerant through a heat exchangerwhile simultaneously conveying a low temperature refrigerant through theheat exchanger, the heat exchanger comprising a plurality of coaxialtubes, each coaxial tube further comprising an outer tube disposedentirely within the accumulator and an inner tube positioned in theouter tube, said inner tube extending through the accumulator, whereinthe high temperature refrigerant flows through the inner tubes and thelow temperature refrigerant flows through the outer tubes.